For legal reasons diverse methods for detecting errors are carried out on emission-relevant control devices in automobiles. For different strategies the law demands a specific frequency of execution per driving cycle. In such cases the new driving cycle begins when the engine is started up again (after previously switching off the ignition key) and ends with the beginning of the subsequent driving cycle. The driving cycle consists in such cases as a rule of different driving modes of which some can be more or less suitable for diagnosis and adaptation purposes. The overrun cut-off is relevant for specific diagnosis and adaptation. The longer a driving cycle lasts, the longer the required driving mode is usually also available.
In many cases a similar method is employed both for the diagnosis and also for adaptation of the system. In such cases however the error detection and the adaptation cannot be activated or carried at the same time, but one after the other. This means that either the system is adapted more slowly or a diagnosis does not take place sufficiently often. In other words in the prior art a method is used in which the diagnosis and the adaptation are carried out contiguously in turn for all emission-relevant control devices. The fact that the diagnosis and the adaptation of form a contiguous method however which lasts for the appropriate length of time until all method steps have been run means that for a rather short driving mode which is observed in a driving cycle under some circumstances only an adaptation can typically be carried out but no subsequent diagnosis. Thus under some circumstances the diagnosis cannot be carried out sufficiently frequently in the driving cycle for the driving modes observed therein, as is defined for example by statutory requirements. In the past diagnosis methods were fast enough to fulfill the frequencies of execution of a diagnosis. Such an adaptation could be used directly as diagnosis. Only in more recent, especially slow, adaptations is a separation of adaptation necessary in order to guarantee the necessary frequency of execution for the diagnosis.
No strategy which must be exclusively activated for an adaptation and diagnosis is known thus far from the prior art.
Furthermore a fuel injection quality monitoring is known from the ISOR (initial statement of reasons) of the CARB (California Air Resource Board) which is based on an engine speed evaluation in the overrun cut-off phase for the injection of defined minimum quantities. The execution of a type of diagnosis and adaptation is merely described in general terms here.
A method is also known from DE 102 57 686 A1 for adapting an injection characteristic. In this case an injection valve characteristic reflecting a reference injection behavior of an activated fuel injection valve is adapted to ageing-related changes of an actual injection behavior. In this case the injection valve is activated intermittently during an operating state in which no fuel injection is required. In this case at least one operating cycle proceeds with activation of an operating cycle without activation of the injection valve. In this case a respective speed value of the internal combustion engine is detected for the operating cycle with activation and at least one for the operating cycles without activation. A correction of the injection characteristic is then undertaken based on the difference between the detected values.